Method of molding strain insulators



arch 5 F. H. TUPPER METHOD OF MOLDING STRAIN INSULATORS Filed Marchas, 1924 vs sheets-sheet 1 MII INVENToR Han/c H 7520/061" ATTORNEY WITNESSES:

l, 2l, March 15, 1927. F. H. TUPPER 6 042 METHOD OF MOLDING STRAIN INSULATORS Filed March 29. 1924 3 sheets-sheet 2 f 1, 21, 42y March 15,1927. I FH'TUPPER v 6 0 METHOD OF MOLDING STRAIN INSULATORS Filed March 29. 1924 5 Sheets-Sheet 5 Ilv WITNEssEs: mvENToR /f fa/7k /2 /lo/oer WZ'. d /L, BY

' ATTORNEY Patented Mar. 15, 1927. y i

UNITE FRANK H'. TUPPER,

ELECTRIC & MANUFACTURING COMP My invention relates to molding, and particularly to molding of the type whereby articles are formed under heat and pressure from impregnated sheet material.

One of the objects of my invention is to provide a process of articles in a single operation under heat and pressure from sheets material.

Another object o provide a mold which shall form a plurality of molded articles from the same sheets of impregnated material in a single operation.

My invention is directed to a mold adapted to be used with sheets of impregnated fibrous material, wherein the excess of molding material and the mater pinched off.'

In molding articles from fibrous impregnated materials under heat and pressure, it

is the usual practice pregnated material shape of the finished article and to mold them separately.

The procedure of from comminuted molding material is to preform asheet of the material to facilitate andling and then to mold the articles and cure the binder in a gang mold with heat The properties of the article to be molded also depend somewhat on the and pressure.

nature of the impr An article molded from fibrous sheet material has great strength and an article made from a comminuted material has a good finish but it does not have a particularly high tensile Consequently,

strength. sired in the finishe large where great tensile sulating properties are desired, the process measure, both the material to be molded and the method vof molding.

For the purpose of molding small objects,

such as strain insulators, rods,

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L T .FPi

0F WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGI-IOUSE METHOD OF HOLDING STRAIN IN'fU'IiAIORS.y

Application filed March 29, 1924. Serial No. 702,726. i

employing sheets of comii'iinuted material. molding a plurality ot assembled mold.

ial between the articles separated from Fig.

s analogus td Fig. 7 is Fig. 2. to cut the sheets of 1mto approximately the fibres and a gang mo having great tensile strengt in a manner similar to that used inmolding view taken on the line V Fig. 8 is a fragmentary cr view taken on the line -VIII-'VIII of Fig. 9 is a plan view formed in the mold, and

Fig. 10 is a View, partially in elevation and 85 ANY, A CORPORATION OF PENNSYLVANIA.

impregnated felted ld whereby articles h may be molded In the drawings constituting a part hereof, and in which like characters designate like partially in end elevation, and'partially in cross section, of my 65 Fig. 2 is a plan view of my mold with a part of the top sect-ion broken away.

Fig. 3 is an end elevational view o Fig. 4 is a4 view, similar to Fig. 3 but with the mold in closed position.'l

Fig. 5 is a side elevational view mold in closed position.

6 is a fragmentary cross sectional View taken on the line VI--VI of Fig. 2.

a fragmentary cross sectional ii-fvii of Fig. e.

oss sectional of the of a strain insulator partially iii cross section, of the strain iiimolding small articles sulator.

ity of articles 1 may egnated material used.

parts of ment. Each and the like,

strength as well as in- Tlie mold is so construe operation and comprises matrix 2 and an yupper which is machined to give the required shapil to the finished article.-

Pins 4 in the matrix and openings 5 in the upper platen are so located that the two 95 the mold are held in exact alignsection of the mold is surrounded by a narrow partition or separator 6 which serves to pinch off the molding niaterial between the molded articles and at' 100 the 'ends and sides of the mold. Open grooves 7 are formed at the sides between the platens and circular enclosed grooves 8 are formed at the ends of the plat-ens to receive the excess molding material.

In order to separate the platens, I haveI ted that a pluralbe molded in a single a lower platen or platen 3, each of of molding each separately from sheets of provided an extension 9 on the upper platen fibrous material is extremely slow and tedious. My invention avoids the former prac# tice of molding each article separately by 3 by'means of which the assembled mold -may be suspended in a standard or yoke 10.

Pins 11 in a plate 12 extend through open- 110 the mold with molding material therein prior 70 tothe molding operation.

ings 13 in the upper platen 3 and are` pressed against the lower platen 2, thereby separating the two parts ot the mold.

I have found that an impregnated cotton felt is suitable for use in my process, although any iibrous felt material which is capable of being pinched ott in the molding operation may be used. The impregnated ielted material 14 is placed between the platens, as shown in Fig. 3. When the plates are pressed together by means of the press platens l5 and' 16, the impregnated material is caused to vtill each individual mold. The edges oit the upper and lower :,'eparators 6 simultaneously pinoli the material between the same. The application of heat and pressure causes the binder to soften and the separators then pinch oti the molded material. The further application ot' heat cures the phenolic condensation product and results in an article having a finished appearance.

kThe mold illustrated is for forming a plurality of strain insulators. The insulators -16, Fig. 9, is provided at each end with a longitudinal groove 17 extending inwardly as tar as the round indented portions 18 near the ends thereot'. When' molded, a thin diaphragm 19 which remains in each of the round indented por-v tions, is afterwards punched or drilled out. I have provided a process of forming a plurality of articles from sheets of imi pregnated fibrous material with heat and pressure which comprises using a material capable of being pinched off when subjected to heat and pressure and using a gang mold whereby each finished article is separated in the molding operation.

Although I have described a specific embodiment ot my invention, I do not w'ish to limit it thereto. For example, I have specitically described a mold for small flat strain insulators, but' the process may be applied ioother shapes, such as rods. Instead ot' a cotton felted material which is impregnated with a phenolic condensation product, I may use other felted material capable of being pinched oti in a mold, or any other binder capable of being cured under heat and pressure, such as shellac. Still other modifications will readily suggest themselves to those skilled in the art, without departing from the spirit ot' my invention, the scope ot which is set forth in the annexed claims.

I claim as my invention:

1. rl`he process of forming a plurality of articles in rone-operation which comprises compressing felted sheet material impregnated with a binder capable of being cured under heat and pressure in a mold, segregating vsaid articles in said molding operation and applying heat and pressure to harden said binder.

2. The process of forming a plurality of articles in one operation which comprises compressing felted cotton material impregnated with a binder capable of being cured under heat and pressure in a mold, segregating said articles in said molding operation and applying heat and pressure to.

harden said binder.

3. The process of forming a plurality of articles in one operation which comprises compressing felted spinnable sheet material impregnated with a binder capable of being cured under heat and pressure in a mold, segregating the excess of said fclted material, pinching said felted material to separate said articles in the molding operation Aand applying heat and pressure to harden said binder.

et. The process of forming a plurality ot articles in one operation' which comprises compressing felted sheet cotton impregnated with a binder capable of being curedl underthe forming operation and applying heat and pressure to harden said condensation product. ,l

6. The process of forming a plurality ot articles in one operation which comprises ycompressing in a mold elted spinnable ibres impregnated with a phenolic condensation product, segregating said articles in said forming operation and'applying heat and pressure to harden said phenolic condensation product. y

7. The process of forming a plurality of articles in one operation which comprises compressing in a mold felted sheet cotton impregnated with aphenolic condensation product, segregating said articles in said forming operation and applying heat and pressure to harden said phenolic condensation product.

8. The process of forming a plurality of articles in one operation which comprises compressing ina mold spinnable felted material impregnated with a phenolic condensation product, segregating the excess of said elted material, pinching said felted material in the molding operation to segregate said articles, and applying heat and pressure to harden said binder.

In testimony whereof, I have hereunto.

subscribed my name this 20th day ost'March, 1924.

FRANK n. Torres. 

